Pupil dilation patterns reflect the contents of consciousness

•We tested whether pupil dilation patterns reflect what people are attending.•Subjects attended to one music clip while another clip played in their other ear.•Pupil dilation patterns reflected which music clip was attended.•Attention-associated dilation patterns could be detected on a single trial.•Deconvolution can reveal the timing and salience of events that evoke dilations. The study of human consciousness has historically depended on introspection. However, introspection is constrained by what can be remembered and verbalized. Here, we demonstrate the utility of high temporal resolution pupillometry to track the locus of conscious attention dynamically, over a single trial. While eye-tracked, participants heard several musical clips played diotically (same music in each ear) and, later, dichotically (two clips played simultaneously, one in each ear). During dichotic presentation, participants attended to only one ear. We found that the temporal pattern of pupil dilation dynamics over a single trial discriminated which piece of music was consciously attended on dichotic trials. Deconvolving these pupillary responses further revealed the real-time changes in stimulus salience motivating pupil dilation. Taken together, these results show that pupil dilation patterns during single-exposure to dynamic stimuli can be exploited to discern the contents of conscious attention.